Variable voltage control system and method for hybrid vehicle

Abstract

A system for controlling voltage to be supplied to electronic devices in a hybrid vehicle that includes: a main battery for storing power to be supplied to a motor of the vehicle; a sub-battery for storing power to be supplied to electronic devices of the vehicle; a low-voltage DC/DC converter (LDC) for converting a high voltage of the main battery into a low voltage and providing the low voltage to the sub-battery and the electronic devices; and a power controller for controlling power of the main battery, the LDC, and the sub-battery. The power controller controls the voltage to be supplied to the electronic devices with a low voltage, a reference voltage higher than the low voltage, and a high voltage higher than the reference voltage in accordance with an idle stop state, a constant velocity traveling state, an acceleration state, and a deceleration state of the vehicle.

What is claimed is: 
     
       1. A variable voltage control system for a hybrid vehicle, the system comprising:
 a main battery for storing high-voltage power to be supplied to a motor of the vehicle; 
 a sub-battery for storing low-voltage power to be supplied to electronic devices of the vehicle; 
 a low-voltage DC/DC converter (LDC) for converting the high-voltage power of the main battery into the low-voltage power to be supplied to the electronic devices; 
 a power controller for controlling the main battery, the LDC, and the sub-battery, 
 wherein the power controller performs variable voltage control using a low voltage, a reference voltage higher than the low voltage, and a high voltage higher than the reference voltage in accordance with an idle stop state, a constant velocity traveling state, an acceleration state, and a deceleration state of the vehicle; and 
 an air conditioner of the vehicle, 
 wherein when the air conditioner is turned on the power controller performs the controlling of the main battery, the LDC, and the sub-battery at the reference voltage when a gear is at a parking position or a neutral position, at the low voltage when the gear is at other stages and an amount of blowing is maximal, and at the low voltage and the reference voltage when the gear is at the other stages and the amount of blowing is not maximal. 
 
     
     
       2. The system as defined in  claim 1 , wherein the control by the power controller is performed:
 alternately at the low voltage and the reference voltage, when the vehicle is in the idle stop state; 
 alternately at the low voltage and the reference voltage, when the vehicle is in the constant velocity traveling state; 
 at the low voltage if the power required for the electronic devices is not higher than a predetermined value, and at the reference voltage if the power required for the electronic devices is higher than the predetermined value, when the vehicle is in the acceleration state; and 
 at the high voltage when the vehicle is in the deceleration state, 
 wherein control time of the alternate control is variable. 
 
     
     
       3. The system as defined in  claim 1 , wherein when at least one headlamp of the vehicle is turned on or at least one wiper of the vehicle is operated, the control by the power controller is performed at the reference voltage. 
     
     
       4. The system as defined in  claim 1 , wherein, the control by the power controller is performed such that the power from the main battery or the sub-battery can be supplied to the electronic devices, the power generated by the motor can be supplied to the electronic devices without using the power from the main battery or the sub-battery, or the power for charging the main battery can be supplied to the electronic devices depending on charging state of the main battery.